Pop out tabs to new window

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "Pop out tabs to new window",
  "version": "1.1",
  "description": "Click the extension's toolbar button to pop out selected tab(s) to a new window.",
  "manifest_version": 2,
  "background": {
    "persistent": true,
    "scripts": [
      "background.js"
    ]
  },
  "offline_enabled": true,
  "browser_action": {
    "default_title": "Pop out tabs to new window"
  },
  "commands": {
    "popout_action": {
      "suggested_key": {
        "default": "Alt+P"
      },
      "description": "Pop out tabs to new window"
    }
  }
}